Deputy Foreign Minister Sergei Ryabkov also said the six global powers seeking to ensure that Iran does not develop nuclear weapons should affirm they are ready for fresh contacts with Tehran on its atomic program, according to the reports.

Ryabkov spoke two days after the Russian state company that built the Bushehr plant, a politically charged project that has run into many delays, said the reactor had begun operating at a low level for tests before it is brought on line.

"The final launch of Bushehr is a matter of the coming weeks," state-run RIA quoted Ryabkov as saying.

"This is a longstanding project and so I would refrain from naming concrete dates -- but we are already on the threshold of the full launch of the reactor."

Begun in the 1970s by a German consortium, the project was abandoned after Iran's 1979 Islamic Revolution. Its completion has been postponed many times since Russia took it over in the mid-1990s under a $1-billion deal with Tehran.

Iran began loading fuel into Bushehr and it had been expected to go online early this year, but it encountered more delays including what officials said was a technical problem that required removal of the fuel assemblies.

"We are proceeding under a schedule agreed with our Iranian partners after the well-known episode involving removal of fuel from the reactor's active zone," Ryabkov was quoted as saying.

On Monday, a member of an Iranian parliamentary commission monitoring Bushehr said "final tests" were being conducted, and Iran's Fars news agency said the plant would start providing power to the national grid within two months.

Using nuclear fuel from Russia, the Bushehr plant's single reactor is to produce 1,000 megawatts, about 2.5% of Iran's electricity usage.

Oil-producing Iran says it plans a network of nuclear power plants and that its nuclear program is for peaceful purposes.

The United States and other Western nations for years urged Russia to abandon the Bushehr project, fearing it would help Iran develop the means to produce nuclear weapons.

An agreement obliging Tehran to repatriate the reactor's spent nuclear fuel to Russia eased those concerns, because such fuel can be reprocessed into plutonium for the core of bombs.

But Iran has rejected international calls for a halt to uranium enrichment at a complex separate from Bushehr, despite intermittent talks with global powers and four rounds of U.N. Security Council sanctions meant to rein in enrichment activity.

Highly enriched uranium can also fuel atomic bombs. Iran says it is refining uranium only to low levels for power plants.

The most recent negotiations with Iran failed in January.

The European Union said on Wednesday that Tehran's response to an EU letter aimed at reviving talks with the six powers -- Russia, China, the United States, Britain, France and Germany -- did not appear to justify another meeting.

Ryabkov also said Iran's response was too vague but added that it was "an important signal, and it is necessary for the 'sextet' to affirm its readiness for contacts," RIA reported.